title: A novel Rieske-type protein derived from an apoptosis-inducing factor-like (AIFL) transcript with a retained intron 4 induces change in mitochondrial morphology and growth arrest.
abstract: Apoptosis-inducing factor-like (AIFL) protein contains a Rieske domain and pyridine nucleotide-disulfide oxidoreductase (Pyr_redox) domain that shows 35% homology to that of apoptosis-inducing factor (AIF) protein. We identified a novel major transcript of the medaka (Oryzias latipes) AIFL gene that retained intron 4 (AIFL-I4) in embryos and tissues from adult fish. The product of this transcript, AIFL-I4 protein, lacked the Pyr_redox domain because of a nonsense codon in intron 4. Both AIFL-I4 and full-length AIFL (fAIFL) transcripts were highly expressed in the brain and late embryos, and relative fAIFL and AIFL-I4 expression levels differed among tissues. Transient expression of AIFL-I4 and fAIFL tagged with GFP showed that AIFL-I4 localized in the nucleus, while fAIFL localized throughout the cytoplasm. We also found that overexpression of AIFL-I4 induced a change in mitochondrial morphology and suppression of cell proliferation. AIFL-I4 mutant with a lesion in [2Fe-2S] cluster binding site of the Rieske domain did not induce these phenotypes. This report is the first to demonstrate nuclear localization of a Rieske-type protein translated from the AIFL gene. Our data suggested that the [2Fe-2S] cluster binding site was essential for the nuclear localization and involved in mitochondrial morphology and suppression of cell proliferation.
authors.affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan. 97318@ib.k.u-tokyo.ac.jp
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Murata
authors.forename: Isao
authors.initials: I
authors.lastname: Furuyama
authors.forename: Shoji
authors.initials: S
authors.lastname: Oda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mitani
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D051033:Apoptosis Inducing Factor / Q000235:genetics*; D002453:Cell Cycle; D049109:Cell Proliferation; D014450:Electron Transport Complex III / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D009990:Oryzias / Q000196:embryology / Q000235:genetics*; D017434:Protein Structure, Tertiary; D014158:Transcription, Genetic
chemical_list: D051033:Apoptosis Inducing Factor; C037989:Rieske iron-sulfur protein; D014450:Electron Transport Complex III